// Copyright (c) 2012 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.

#ifndef CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
#define CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_

#include <stddef.h>
#include <stdint.h>

#include "base/macros.h"
#include "base/observer_list.h"
#include "content/browser/renderer_host/render_process_host_impl.h"
#include "content/common/content_export.h"
#include "content/public/browser/render_process_host_observer.h"
#include "content/public/browser/site_instance.h"
#include "url/gurl.h"

namespace content {
class BrowsingInstance;
class RenderProcessHostFactory;

class CONTENT_EXPORT SiteInstanceImpl final : public SiteInstance,
                                              public RenderProcessHostObserver {
public:
    class CONTENT_EXPORT Observer {
    public:
        // Called when this SiteInstance transitions to having no active frames,
        // as measured by active_frame_count().
        virtual void ActiveFrameCountIsZero(SiteInstanceImpl* site_instance) { }

        // Called when the renderer process of this SiteInstance has exited.
        virtual void RenderProcessGone(SiteInstanceImpl* site_instance) = 0;
    };

    static scoped_refptr<SiteInstanceImpl> Create(
        BrowserContext* browser_context);
    static scoped_refptr<SiteInstanceImpl> CreateForURL(
        BrowserContext* browser_context,
        const GURL& url);

    // SiteInstance interface overrides.
    int32_t GetId() override;
    bool HasProcess() const override;
    RenderProcessHost* GetProcess() override;
    BrowserContext* GetBrowserContext() const override;
    const GURL& GetSiteURL() const override;
    scoped_refptr<SiteInstance> GetRelatedSiteInstance(const GURL& url) override;
    bool IsRelatedSiteInstance(const SiteInstance* instance) override;
    size_t GetRelatedActiveContentsCount() override;
    bool RequiresDedicatedProcess() override;
    bool IsDefaultSubframeSiteInstance() const override;

    // Returns the SiteInstance, related to this one, that should be used
    // for subframes when an oopif is required, but a dedicated process is not.
    // This SiteInstance will be created if it doesn't already exist. There is
    // at most one of these per BrowsingInstance.
    scoped_refptr<SiteInstanceImpl> GetDefaultSubframeSiteInstance();

    // Set the web site that this SiteInstance is rendering pages for.
    // This includes the scheme and registered domain, but not the port.  If the
    // URL does not have a valid registered domain, then the full hostname is
    // stored.
    void SetSite(const GURL& url);
    bool HasSite() const;

    // Returns whether there is currently a related SiteInstance (registered with
    // BrowsingInstance) for the site of the given url.  If so, we should try to
    // avoid dedicating an unused SiteInstance to it (e.g., in a new tab).
    bool HasRelatedSiteInstance(const GURL& url);

    // Returns whether this SiteInstance has a process that is the wrong type for
    // the given URL.  If so, the browser should force a process swap when
    // navigating to the URL.
    bool HasWrongProcessForURL(const GURL& url);

    // Increase the number of active frames in this SiteInstance. This is
    // increased when a frame is created, or a currently swapped out frame
    // is swapped in.
    void IncrementActiveFrameCount();

    // Decrease the number of active frames in this SiteInstance. This is
    // decreased when a frame is destroyed, or a currently active frame is
    // swapped out. Decrementing this to zero will notify observers, and may
    // trigger deletion of proxies.
    void DecrementActiveFrameCount();

    // Get the number of active frames which belong to this SiteInstance.  If
    // there are no active frames left, all frames in this SiteInstance can be
    // safely discarded.
    size_t active_frame_count() { return active_frame_count_; }

    // Increase the number of active WebContentses using this SiteInstance. Note
    // that, unlike active_frame_count, this does not count pending RFHs.
    void IncrementRelatedActiveContentsCount();

    // Decrease the number of active WebContentses using this SiteInstance. Note
    // that, unlike active_frame_count, this does not count pending RFHs.
    void DecrementRelatedActiveContentsCount();

    void AddObserver(Observer* observer);
    void RemoveObserver(Observer* observer);

    // Sets the global factory used to create new RenderProcessHosts.  It may be
    // NULL, in which case the default RenderProcessHost will be created (this is
    // the behavior if you don't call this function).  The factory must be set
    // back to NULL before it's destroyed; ownership is not transferred.
    static void set_render_process_host_factory(
        const RenderProcessHostFactory* rph_factory);

    // Get the effective URL for the given actual URL.  This allows the
    // ContentBrowserClient to override the SiteInstance's site for certain URLs.
    // For example, Chrome uses this to replace hosted app URLs with extension
    // hosts.
    // Only public so that we can make a consistent process swap decision in
    // RenderFrameHostManager.
    static GURL GetEffectiveURL(BrowserContext* browser_context,
        const GURL& url);

    // Returns true if pages loaded from |url| ought to be handled only by a
    // renderer process isolated from other sites. If --site-per-process is on the
    // command line, this is true for all sites. In other site isolation modes,
    // only a subset of sites will require dedicated processes.
    static bool DoesSiteRequireDedicatedProcess(BrowserContext* browser_context,
        const GURL& url);

private:
    friend class BrowsingInstance;
    friend class SiteInstanceTestBrowserClient;

    // Create a new SiteInstance.  Only BrowsingInstance should call this
    // directly; clients should use Create() or GetRelatedSiteInstance() instead.
    explicit SiteInstanceImpl(BrowsingInstance* browsing_instance);

    ~SiteInstanceImpl() override;

    // RenderProcessHostObserver implementation.
    void RenderProcessHostDestroyed(RenderProcessHost* host) override;
    void RenderProcessWillExit(RenderProcessHost* host) override;
    void RenderProcessExited(RenderProcessHost* host,
        base::TerminationStatus status,
        int exit_code) override;

    // Used to restrict a process' origin access rights.
    void LockToOrigin();

    // This gets the render process to use for default subframe site instances.
    RenderProcessHost* GetDefaultSubframeProcessHost(
        BrowserContext* browser_context,
        bool is_for_guests_only);

    void set_is_default_subframe_site_instance()
    {
        is_default_subframe_site_instance_ = true;
    }

    // An object used to construct RenderProcessHosts.
    static const RenderProcessHostFactory* g_render_process_host_factory_;

    // The next available SiteInstance ID.
    static int32_t next_site_instance_id_;

    // A unique ID for this SiteInstance.
    int32_t id_;

    // The number of active frames in this SiteInstance.
    size_t active_frame_count_;

    // BrowsingInstance to which this SiteInstance belongs.
    scoped_refptr<BrowsingInstance> browsing_instance_;

    // Current RenderProcessHost that is rendering pages for this SiteInstance.
    // This pointer will only change once the RenderProcessHost is destructed.  It
    // will still remain the same even if the process crashes, since in that
    // scenario the RenderProcessHost remains the same.
    RenderProcessHost* process_;

    // The web site that this SiteInstance is rendering pages for.
    GURL site_;

    // Whether SetSite has been called.
    bool has_site_;

    // Whether this SiteInstance is the default subframe SiteInstance for its
    // BrowsingInstance. Only one SiteInstance per BrowsingInstance can have this
    // be true.
    bool is_default_subframe_site_instance_;

    base::ObserverList<Observer, true> observers_;

    DISALLOW_COPY_AND_ASSIGN(SiteInstanceImpl);
};

} // namespace content

#endif // CONTENT_BROWSER_SITE_INSTANCE_IMPL_H_
